Furnace header box



FURNACE HEADER BOX Filed Jan. 4, 1949 a 00 5 as 26 as filo,

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ATTORNEY.

Patented June 5, 1951 FURNACE HEADER BOX John Litell, Laurelton, and John S. Wallis, New York, N. Y., assignors to Petro-Chem Process Company, Incorporated, New York, N. Y., a

corporation of Delaware Application January 4, 1949, Serial No. 69,162

2 Claims. 1 This invention pertains to the upper header boxes of vertical furnaces or boilers.

It has been customary to use fiat header boxes in which structural steel members within the boxes carry the bending moments of the stack."

The usual header box was horizontal, rectangular in cross-section, and covered with flat plates or doors with the structural supporting members inside the box.

That arrangement has some disadvantages. For instance, if there was a leak in the furnace headers which resulted in a fire, the structural members were liable to fail due to the intense heat within their restricted space.

Also, it was very diilicult to make the header box waterproof because the horizontal plates did not readily shed rain water flowing down the stack onto the horizontal box covers.

An object of the present invention is to over come the above disadvantages by replacin the fiat header box and its internal members with an arrangement comprising a truncated, conical, structural-steel framework having header box plates in the form of segments bolted to the insides of the steel framework.

Thus, the structural members are all external to the header box compartments, and the conical plates form a construction bolted to those same members, and readily made waterproof.

Another object is to provide a convenient trough like receptacle around the header box for accommodating spare fittings, and operators tools.

Further and other objects will be apparent from the specification and claims, and from the :35

accompanying drawings which illustrate what is now considered to be a preferred embodiment of the invention.

In the drawings:

Figure 1 is an elevation of a furnace embodyc in the invention, shown partly in cross-section;

Fig. 2 is an enlarged sectional detailed view of the invention which is shown generally in Fig. 1; and

Fig. 3 is a detailed view on line 3-3 of Fig. 2.

The vertical tube furnace illustrated has a cylindrical furnace shell Ml surrounding an annula bank of tubes :6, an annular horizontal segmental tube sheet 52 near the top of the furnace shell through which the tubes extend at the top, an upper cylindrical shell 36 of smaller diameter than the furnace shell Ml extending upwardly from the inner edge of the annular tube sheet 52 and a segmental frusto-conical outer shell 31! forming, together with the tube sheet and the upper cylindrical shell, an annular header box for the upper ends of the tubes, and an outer structural frame composed of vertical beams 24 circumferentially spaced about the outer surface of the cylindrical furnace shell IE3, having inwardly inclined upper ends or extension beams 22 from which the frusto-conical sections 3% of the header box are removably affixed and horizontal rings 38 and 26 which tie the vertical beams together at the top and approximately at the level of the tube sheet. The header box is shaped in cross section substantially like a right triangle. More specifically, the acute angles of said triangle are cut oif near their apices by the shell Ill and a ring 32, to be described. The inclined upper ends or extension beams 22 are preferably joined to the beams 24 and to the structural steel ring 26 by welding. The furnace shell I 83 is lined with rockwool in sulation M and fire brick E2. The vertical furnace tubes It may have fins l8. Tubes it are joined in pairs by return bends 2!! at their upper ends.

Ring 26 is preferably of channel shape, as illustrated. thereby forming a trough-like shelf adapted for holding operators tools and pipe fit-- tings, during cleaning operations.

The header box plates are in the form of curved segments 39 bolted to the inner flanges of beams 22 as shown in detail in Fig. 3. Bolts 3| are screwed into nuts 33 tack welded on the inner faces of segments 3!] so that the segments may readily be removed and replaced. Also, for convenience, segments 3!! may be provided with welded-on handles, not shown.

The upper ends of segments 38 are bolted to a ring 32 welded at 34 to a vertical cylindrical shell 3%, which is supported at its upper end by angle rings 38 welded to beams 22. Attached to the cylindrical shell 55 are angle brackets is, which, through vertical rods 32, support the usual furnace cone (not shown).

Atmospheric air enters the cylindrical shell 36 through holes 42, and passes downwardly, as indicated by arrows, into the furnace between the cylindrical shell 36 and a concentric shell 44, as indicated by arrows. Shell 44 is supported at its upper end by a radially extending flange 4t clamped between angle ring 33 and a cooperating angle ring 48, which also supports stack 50.

Tubes !6 are held in position by the tube sheet formed of segmental units 52 bolted to brackets 54 attached to the bottom of the cylindrical shell 36, and to brackets 55 welded to the shell It.

It is to be understood that the invention is not 3 limited to the specific embodiment herein illustrated and described, but may be used in other ways Without departure from its spirit as defined by the following claims.

We claim:

1. A vertical tube furnace having an annular bank of tubes, .a cylindricaliurnace .shell surrounding the tubes, an annular horizontal tube sheet near the top of the furnace shell through which the tubes extend, an upper cylindrical shell of smaller diameter than the furnace shell extending upwardly from the inner edge of the annular tube sheet and a segmentallfrustoeconical outer shell making a substantial angle with said tube sheet and forming together with 'the tube sheet and the upper shell an annular header box of substantially triangular cross-section for the upper ends of the tubes, an outer structural frame composed of vertical beams circumferentially spaced about the outertsurface of the cylindrical furnace,shelhhavinginwardlyinclinedlupperlextensionabeams to which the ,fnusto-conical sectionsof the header boxiare removablyaffixed-rand horizontal :ring ibeams at the tube sheet and .at

:the top .of the .header box, and means =attaching Hsaid-extension-beams to said rings.

.4 2. The invention set forth in claim 1 in which the ring beam at the level of the tube sheet is in the form of a channel to constitute a trough-like receptacle for fittings and equipment of the operator.

JOHN LITELL. JOHN S. WALLIS.

REFERENCES CITED The following references are of record in the .file of this patent:

UNITED STATES PATENTS Number .Name Date 1294,4951 (Allen Mar. 11, 1884 $291,381 Go dfrey Apr. 22, 1884 441,273 .Baker Nov. 25, 1890 r 812,668 Moran Feb. 13, 1906 12340287 Throckmorton et a1. Feb. 1, 1944 2,342,011 Rickerman Feb. 15, 1944 ..2,385,749 Wallis etial. .-=Se'pt. 25, 1945 2,389,622 .Hensel .Nov..27, 1945 "2,454,943 ,Reed.. Novn30, 1948 

